1. Technical Field
The present invention relates to a technology of an image display device, in particular, an image display device in which laser light modulated in accordance with an image signal is made to transmit a screen to display an image.
2. Related Art
In recent years, a laser projector where an image is displayed with laser light is proposed. The laser light is high in the monochromaticity and directivity. Accordingly, the laser projector has an advantage in that an image excellent in the color reproducibility can be obtained. In the laser projector, such a measure is taken that a light source that supplies the laser light is hermetically sealed in a chassis and only laser light that is dispersed in the intensity owing to scanning is supplied outside of the chassis, and thereby laser light larger in the intensity than a predetermined intensity is inhibited from coming out of the chassis. As a result, for instance, when such an anomaly that while the laser light is supplied from the light source the laser light is stopped in scanning is caused, in some cases, laser light larger in the intensity than a predetermined intensity may be exited outside of the chassis. A technology that avoids a case where laser light larger in the intensity than a predetermined intensity is exited outside of the chassis is proposed in, for instance, JP-A No. 2002-281532.
The technology proposed in JP-A No. 2002-281532 is constituted so that when a phenomenon that may cause a case where the laser light large in the intensity is exited outside of the chassis is detected, the laser light is shut via a control circuit. In the case of such a configuration, since an anomaly is considered caused in the control circuit as well, it is difficult to assuredly cut the laser light. As a configuration with which the laser light is shut without intermediates of the control circuit, it is considered to use an optical member that is damaged or modified owing to irradiation of the laser light larger in the intensity than a predetermined intensity. In this case, when the damaged or modified optical member shuts the laser light, a situation that the laser light large in the intensity is exited outside of the chassis can be avoided. In the case of such a configuration, the laser light can be shut from emitting outside. However, when the control circuit is not used together, the laser light is continued supplying inside of the chassis. From this, in the case where an anomaly is caused in the scanning of the laser light, it is considered that, owing to the continuation of supply of the laser light inside of the chassis, in some cases, an inconvenience such as the damage of a device may not be avoided. Thus, in an existing technology, there is a problem in that when an anomaly is caused in the scanning of beam-like light, in some cases, an inconvenient situation may not be avoided from occurring.